Retinal degenerative diseases such as age-related macular degeneration are associated with dysfunction and deterioration of the rod and cone photoreceptors of the retina. Postsynaptic membrane receptor proteins of retinal neurons proximal to the rods and cones mediate the transmission of visual signals at multiple types of chemical synapses in the normally functioning retina, and there is reason to believe that these proximal retinal neurons in certain cases remain functional despite the disease-induced loss of rod and cone visual signaling. The long-term goal of the proposed project is to design and construct nanoscale molecular structures that can selectively attach to the extracellular face of specific membrane receptors of post-photoreceptor retinal neurons and, by modulating the postsynaptic receptor's activity in response to light, restore visual signaling in retina damaged by photoreceptor degenerative disease. In this application we propose a 5-year project aimed at this challenging bioengineering objective. The research will involve closely integrated studies employing molecular biology, organic synthesis, and biophysical/ electrophysiological analysis of prototype systems. A main focus of the proposed experiments is the GABAC receptor, a membrane receptor protein of retinal bipolar cells whose known properties make it well suited as a model system. Leading the research will be David R. Pepperberg, PhD, Principal Investigator (Ophthalmology and Visual Sciences, Univ. of Illinois at Chicago (UIC)); and Co-Investigators Karol S. Bruzik, PhD (Medicinal Chemistry and Pharmacognosy, UIC), Tejal A. Desai, PhD (Biomedical Engineering, Boston Univ.), Jack H. Kaplan, PhD (Biochemistry and Molecular Genetics, UIC), Brian K. Kay, PhD (Biosciences Division, Argonne National Laboratory), Nalin M. Kumar, PhD (Ophthalmology and Visual Sciences, UIC), Guy C. Le Breton, PhD (Pharmacology, UIC), Jie Liang, PhD (Bioengineering, UIC), Haohua Qian, PhD (Ophthalmology and Visual Sciences, UIC), Sandra J. Rosenthal, PhD (Chemistry, Vanderbilt Univ.), and Robert F. Standaert, PhD (Chemistry, UIC). Lay language summary: The project's objective is to develop molecular structures that can restore vision in photoreceptor degenerative diseases such as age-related macular degeneration. These structures will be designed to attach to non-photoreceptor cells of the diseased retina that remain functional and to make these cells responsive to light. [unreadable] [unreadable]